There are a variety of black powder, single shot firearms currently available in the marketplace. These modern weapons are based upon the traditional muzzle loading, black powder weapons of the past, yet they incorporate modern materials and technological advances. Recent improvements have brought such weapons to a modern renaissance by increasing their effectiveness while still relying on a sense of history and tradition important to the contemporary black powder hunter and rifleman.
A major drawback associated with all of such firearms is that they are only currently able to discharge black powder or Pyrodex.RTM.. Even the newest and most advanced muzzle loaders are not designed to withstand the forces and pressures generated by the use of smokeless powder as a propellant in single shot muzzle loading weapons. In particular, there are strong warnings against discharging smokeless gun powder in such firearms. Smokeless powder is a substantially more powerful propellant which, if improperly used, significantly increases the risk of blow ups.
Not only does smokeless gun powder increase the velocity, accuracy and power available, but smokeless gun powder is much less corrosive than black powder or Pyrodex.RTM. gun powder and a weapon utilizing this propellant thus requires less cleaning or maintenance. Consequently, it is imperative for safety reasons that if smokeless gun powder is to be utilized in a weapon, it is desirable to design a muzzle loader which is capable of safely discharging both black powder or Pyrodex.RTM. gun powder as well as smokeless gun powder.
Typically, black powder and Pyrodex.RTM. gun powders have a standard burn rate which, by contemporary standards, is relatively slow. Upon discharge of the weapon, the powder ignites and burns, causing an explosion force that is generated within the breech end of the gun barrel. The exploding powder causes the projectile, e.g. the slug, round ball or bullet, to be very swiftly conveyed along the length of the gun barrel and discharged out the muzzle end of the gun barrel.
On the other hand, when smokeless gun powder is discharged within a gun barrel, it achieves a drastically increased burn rate compared to that of conventional gun powder. The rapid burn rate produces gases within the breech end of the gun barrel and it is the expansion of such gases that causes the projectile. e.g. the slug, round ball or bullet, to be swiftly forced out of the muzzle end of the gun barrel.
Upon discharging a firearm containing either black powder or Pyrodex.RTM. gun powder, typically a force of about 7,000 to about 20,000 pounds per square inch is generated within the gun barrel, depending upon the quantity or charge of gun powder contained within the gun barrel. Upon discharging a firearm containing smokeless gun powder having the same quantity or charge as with black or Pyrodex.RTM. gun powder, typically a force of between about 20,000 to about 62,000 pounds per square inch or so can be generated within the gun barrel.
It is of the utmost importance when using such a volatile propellent to ensure that substantially all the formed gases are directed down the length of the barrel and out the muzzle end. As is readily apparent from even a basic understanding of expanding gases, any generated gas expansion force not directed down the length of the barrel must be allowed to expended and exhaust somewhere else. Unfortunately, the only other path for the expanding gases is back through the ignition bore or orifice hole, out the breech plug and into the face of the rifleman. Therefore, it is desirable to limit any rapid backward escape of such formed gases through the ignition bore or orifice hole provided in the breech plug supported by the breech end of the gun barrel. If significant excess gases are allowed to escape via the ignition bore or orifice hole, formed in the breach plug, there is a real potential that the breech end of the gun barrel could explode in the face of the operator, burn the face or body part of an operator or otherwise seriously injure or mortally wound the operator.